diff --git a/codegen/type_converter.go b/codegen/type_converter.go
index 5d961e874..b1f8f1670 100644
--- a/codegen/type_converter.go
+++ b/codegen/type_converter.go
@@ -351,10 +351,7 @@ func (c *TypeConverter) genConverterForMap(
 	_, isStringKey := toFieldType.KeySpec.(*compile.StringSpec)
 
 	if !isStringKey {
-		keyType, err := c.getGoTypeName(toFieldType.KeySpec)
-		if err != nil {
-			return err
-		}
+		keyType, _ := c.getGoTypeName(toFieldType.KeySpec)
 		c.appendf(
 			"%s = make(map[%s]%s, len(%s))",
 			toIdentifier, keyType, typeName, sourceIdentifier,